Rodell wants to find the favorite gaming app among the students at his school. He decides to poll the thirty students on his football team and the fifteen students on his basketball team to gather the data. What is wrong with Rodell’s method for collecting his data? Rodell only polled fellow athletes; this sample does not represent nonathletes at the school.
Rodell needs a larger sample size than two sports teams to represent a whole school.
Rodell polled everyone on his teams; he should have only polled every other student for it to be a true sample.
Rodell’s polling method only included fall and winter sports; he should have also included a spring sport like baseball.

Atechnician compares repair costs for two types of microwave ovens (type i and type ii). he believes that the repair cost for type i ovens is greater than the repair cost for type ii ovens. a sample of 6767 type i ovens has a mean repair cost of $79.79$⁢79.79. the population standard deviation for the repair of type i ovens is known to be $19.18$⁢19.18. a sample of 5555 type ii ovens has a mean repair cost of $75.24$⁢75.24. the population standard deviation for the repair of type ii ovens is known to be $21.40$⁢21.40. conduct a hypothesis test of the technician's claim at the 0.050.05 level of significance. let μ1μ1 be the true mean repair cost for type i ovens and μ2μ2 be the true mean repair cost for type ii ovens. step 2 of 4 : compute the value of the test statistic. round your answer to two decimal places.